Clean up Xlib viewer

* Make event handling closer to GLFW's
* Fix Vulkan refreshing

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2226413002

Review-Url: https://codereview.chromium.org/2226413002

3 files changed, 19 insertions, 6 deletions

diff --git a/tools/viewer/Viewer.cpp b/tools/viewer/Viewer.cpp
index da329e0b3e..6f33d2c202 100644
--- a/tools/viewer/Viewer.cpp
+++ b/tools/viewer/Viewer.cpp
@@ -136,6 +136,10 @@ Viewer::Viewer(int argc, char** argv, void* platformData)
     fBackendType = get_backend_type(FLAGS_backend[0]);
     fWindow = Window::CreateNativeWindow(platformData);
     fWindow->attach(fBackendType, DisplayParams());
+#if defined(SK_VULKAN) && defined(SK_BUILD_FOR_UNIX)
+    // Vulkan doesn't seem to handle a single refresh properly on Linux
+    fRefresh = (sk_app::Window::kVulkan_BackendType == fBackendType);
+#endif
 
     // register callbacks
     fCommands.attach(fWindow);
@@ -211,6 +215,10 @@ Viewer::Viewer(int argc, char** argv, void* platformData)
         }
 #endif
         fWindow->attach(fBackendType, DisplayParams());
+#if defined(SK_VULKAN) && defined(SK_BUILD_FOR_UNIX)
+        // Vulkan doesn't seem to handle a single refresh properly on Linux
+        fRefresh = (sk_app::Window::kVulkan_BackendType == fBackendType);
+#endif
 
         this->updateTitle();
         fWindow->inval();
diff --git a/tools/viewer/sk_app/VulkanWindowContext.cpp b/tools/viewer/sk_app/VulkanWindowContext.cpp
index 815e8c43f5..7f35e30f48 100644
--- a/tools/viewer/sk_app/VulkanWindowContext.cpp
+++ b/tools/viewer/sk_app/VulkanWindowContext.cpp
@@ -587,7 +587,6 @@ void VulkanWindowContext::swapBuffers() {
     };
 
     fQueuePresentKHR(fPresentQueue, &presentInfo);
-
 }
 
 }   //namespace sk_app
diff --git a/tools/viewer/sk_app/unix/main_unix.cpp b/tools/viewer/sk_app/unix/main_unix.cpp
index 5e6b7fe3ee..c0fd418262 100644
--- a/tools/viewer/sk_app/unix/main_unix.cpp
+++ b/tools/viewer/sk_app/unix/main_unix.cpp
@@ -26,12 +26,13 @@ int main(int argc, char**argv) {
 
     // Get the file descriptor for the X display
     int x11_fd = ConnectionNumber(display);
-    fd_set in_fds;
+    int count = x11_fd + 1;
 
     SkTHashSet<sk_app::Window_unix*> pendingWindows;
     bool done = false;
     while (!done) {
         // Create a file description set containing x11_fd
+        fd_set in_fds;
         FD_ZERO(&in_fds);
         FD_SET(x11_fd, &in_fds);
 
@@ -40,12 +41,15 @@ int main(int argc, char**argv) {
         tv.tv_usec = 100;
         tv.tv_sec = 0;
 
-        // Wait for an event on the file descriptor or for timer expiration
-        (void) select(1, &in_fds, NULL, NULL, &tv);
+        while (!XPending(display)) {
+            // Wait for an event on the file descriptor or for timer expiration
+            (void) select(count, &in_fds, NULL, NULL, &tv);
+        }
 
         // Handle XEvents (if any) and flush the input 
-        XEvent event;
-        while (XPending(display) && !done) {
+        int count = XPending(display);
+        while (count-- && !done) {
+            XEvent event;
             XNextEvent(display, &event);
 
             sk_app::Window_unix* win = sk_app::Window_unix::gWindowMap.find(event.xany.window);
@@ -73,6 +77,8 @@ int main(int argc, char**argv) {
             app->onIdle();
         }
         pendingWindows.reset();
+
+        XFlush(display);
     }
 
     delete app;